


The Best Prank Yet

by Miss_EmptyFull



Category: Undertale (Video Game)
Genre: Bondage, Comfort, Dom Sans (Undertale), Ecto-Genitalia (Undertale), Ecto-Penis (Undertale), Ecto-Vagina (Undertale), Fluff, Fluff and Smut, Incest, Incest Kink, Kink Exploration, M/M, Multiple Orgasms, No Ecto-Bodies, Oneshot, Overstimulation, Sensitive bones, Sibling Incest, Smut, Sub Papyrus (Undertale)
Language: English
Status: Completed
Published: 2018-09-10
Updated: 2018-09-10
Packaged: 2019-07-10 11:01:26
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,052
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15948014
Author URL: https://archiveofourown.org/users/Miss_EmptyFull/pseuds/Miss_EmptyFull
Summary: Sans comes up with a once-in-a-lifetime prank, specially-made for Papyrus. Said skeleton is woefully under prepared to thwart it, but does he even want to?





	The Best Prank Yet

**Author's Note:**

> A trade for dangerzbone.tumblr.com.

Papyrus grinned to himself as he marched his way home after an uneventful day of patrolling around Snowdin, that the enthusiastic skeleton deemed no less invigorating than the previous ones. Plans for new puzzles were jotted down on a few papers and puzzles that he’d already made had been calibrated to perfection. He thought to himself that it’d be an interesting challenge to time himself each time to see just how fast he could calibrate, he laughed softly to himself and filed the idea away for tomorrow.

Perhaps he’d ask Sans to time him, but then again, his layabout of a brother would likely fall asleep not even a minute into it.

Shaking the thought away, Papyrus strode up to his front door, opened it, and walked inside. As soon as the front door closed behind him, Papyrus’ vision was cut off, shrouding him in darkness. He flailed his arms for a moment, moving to form a bone attack in self defense. But just as orange magic began to gather in his hands, his smelled something sickly sweet and before he knew it, he was waking up in his bed.

Papyrus laid still for a moment, his mind trying to catch up with what had just happened. He had felt something being thrown over his face, he’d tried to defend himself, and now he was in his bed. The lights in his room were off, the only light source he could see creeped in under the door from the hallway.

With a quick and fluid movement he sat up and stood, looking around and moved to scratch at his head before realizing, his wrists were bound. Tied tightly to one another behind his back. How long had he been out of it? What fiend could have done this? But then the thought hit him, he knew exactly what fiend could have done this.

“SANS! IS THIS ONE OF YOUR PRACTICAL JOKES AGAIN?”, he called out into the dark room in annoyance hoping for a response.

“man you caught on to that quick, huh?”, Papyrus jumped as he heard his brother speak from what had to be inside the room. He looked around once more, trying to see his brother and sighed out in relief when he spotted the previously unseen socket and eye light, peering into the room from his closet.

“OF COURSE I DID! HONESTLY SANS, YOU CAN DO BETTER THAN THIS! LIKE THAT ONE TIME WITH THAT ‘SKELETON DOG PRANK’ OR EVEN THE ‘BRIDGE EATING PEOPLE PRANK’!”, Papyrus listed as Sans emerged from his closet to come further into the room.

Sans walked over with his hands stuffed into his pockets and a wide grin on his face, Papyrus sighed and shifted his wrists around. “BUT NEVERMIND THAT. COULD YOU UNTIE ME NOW?”, he said in a slightly subdued voice as he wondered why Sans was staring at him like that.

Sans shrugged and walked closer to his little brother, only to stop just short of a few inches in front of him. Papyrus could feel Sans’ breaths on his chest, deep and hot bursts of air that hit him and made his bones tingle in their wake. Sans’ eyelights were sharp and focused, which was unusual for the lazybones. Papyrus started to hold the stare, trying to figure out what the heck his brother was thinking. As lazy as his brother was, he talked as much as he did, so the silence that carried on between them was unsettling.

For a few moments more, Sans just stared, and just as Papyrus was about to open his mouth to speak to break the unnerving silence, Sans tilted his head.

Not quickly, and not by a lot. It was the subtlest movement, but so obviously intentional, it stopped any thoughts of questioning the situation running in Papyrus’ head. And made him shiver.

He knew what he was feeling right now, and he wanted it to stop. The room was dark, Sans was standing so close, giving him a look that made him feel like he was being stripped on the spot! This was embarrassing! If his magic started to get stimulated, Sans would see! He’d see how much this was turning him on! Deciding his brother couldn’t see him like this, the taller skeleton moved to leave the room, he took one step to the side away from Sans.

Papyrus breathed in sharply and took a step back when he was blocked as Sans teleported to stand right in front of him, balancing on his bedpost to loom over him. Sans’ eyelights emanated magic that made Papyrus’ knees weak and as his brother stood there, he slowly, shook his head ‘no’. Papyrus’ body went aflame in arousal, there was no way this was accidental. But how?

His brother had always been an excellent lover, treating him right, loving him well, making love to him excellently. He was perfect, but Papyrus never told him how he really wanted to be handled in bed. Tied-up, gagged, choked, all as he was fucked into the bed. All of these lewd and sinful thoughts, had been kept to himself, never to leave his mind. So how did his brother suddenly know how to make him tremble without even touching him?

Papyrus felt the back of his legs hit the edge of his bed as Sans hopped down from the bedpost, and stood before him again, trapping him. Like a hunter trapping its prey, Papyrus clenched his teeth to keep himself from whimpering at the thought.

“lie back down.”

The simple yet obvious command was obeyed without question, Papyrus’ magic had long since activated, and was eagerly waiting for stimulation in his shorts. But he didn’t move or even shift to try and give that to himself, he’d been ordered to lie down, not roll around in the bed like a desperate slut - as much as the thought appealed to him. Oh stars he was already dirty talking in his head! What would Sans think if he heard him say something so awful?

Sans looked over Papyrus for a moment more before bringing a very familiar small notepad out of his pocket, the tied up skeleton’s jaw dropped in realization, shock and horror. The Great Papyrus, had made an even greater mistake.

He had let his awful, lewd thoughts leave his mind, in the form of documenting them in the very notepad his brother now held. He knew. He really knew.

“paps.”

Sans’ calm voice broke through his panicked thoughts and he looked over, he expected disappointment, hate, disgust, but not what he did see. A kind and patient smile, that was also a little apologetic. “y’know, you don’t have to be ashamed of this bro.”

Papyrus shook his head, “IT’S GROSS A-AND...YOU READ ALL OF IT DIDN’T YOU? HOW’D YOU EVEN GET IT!” He didn’t realize until he stopped speaking that he was just short of crying from the stress of this new realization.

Sans shrugged, “well i figured you were hiding my ketchup somewhere in here and... but nah, i didn’t read all of it pap. only got past a few things on the first page before realizing what exactly i was lookin’ at. but you’re right about one thing, this stuff is gross, and lewd, borderline lecherous.” Sans leaned down to bow his head over Papyrus’, “and  _really_  fucking hot.”

Papyrus’ eye sockets went wide as he looked at his brother who just gave him the same shit-eating grin as always. “hope you’ll share the rest of this thing with me one day.”, Sans said waving the notepad around before carefully setting it down, “but either way, bro, if you’ll let me... i really wanna try some of that stuff with you? ‘cause i’m hard as hell, and you look like you're really enjoying this.”

Papyrus blinked a few times, “Y-Ou...You’re not disgusted? I was so sure you’d-.”

Sans stood only to climb on top of Papyrus in bed and hover over him with a look clouded in mischief and lust, “i dunno. does it disgust you,  _brother_?”

A shiver ran up Papyrus’ spine and he whimpered, going right for the incest kink right off the bat, wholly unfair. But he felt a wave of relief as Sans was so accepting of these desires of his, and with a tentative breath, Papyrus spoke. “NO NOT AT ALL, B-B-BROTHER...”

“good, ‘cause i really want to...” One of Sans’ hands went to touch Papyrus for the first time that night and grabbed his pelvis, activating the dense fog of eager magic gathered there. Papyrus jolted with a whine of a moan that he had no chance of restraining. “get  _in_  on this, heh.”, at the same time Sans pushed his crotch up against Papyrus’ leg slightly humping him. He could feel the growing hardness against his leg, and whimpered as he imagined it inside him.

“SANS PLEASE!”, Papyrus whined as he felt Sans’ fingers rolling in and massaging his now solid entrance underneath his shorts.

Sans chuckled, “hold up a sec bro, i can’t just fuck ya’ right now! you’re not prepared, not stretched out any, and i’m gonna need some sorta lubrication somewhere. patience, and pap?” With a whimper and shiver, Papyrus met Sans’ gaze, showing he was listening. “i know i taught you better than this, call me ‘brother’ alright? i take care of you your whole life, and i don’t get any respect anymore?”

“NO NO! YOU DO! BROTHER...YOU’VE ALWAYS TAKEN SUCH GOOD CARE OF ME.”, Papyrus played along as Sans pushed at his concealed pussy harder causing him to moan and wriggle slightly in his bindings.

Sans chuckled, “hell yeah i have, and i think i may be spoiling ya’ but im’ma take care of ya’ again tonight alright?”

Papyrus gave his brother a shy smile as he impatiently shifted his hips upwards into the hand holding him, hoping Sans could feel how wet he was despite the layers of fabric. Sans’ eye sockets widened, which gave Papyrus his answer, oh yes his brother could feel how wet his throbbing pussy was.

Sans chuckled and let his head fall, “man oh man, when did my little brother get to be so lewd?” When he looked back up, Papyrus felt his soul throb in want as a singular blue eyelight, sharp and hypnotizing, stared into his very soul in hunger. His shorts were yanked down his legs and two fingers quickly found their way inside of the dripping pussy already ready for something more.  
  


Papyrus moaned as his hips rolled into the fingers impatiently pumping into him, obviously not intending to keep Papyrus waiting any longer. “MM-AAH! M-MMORE BROTHER! PLEASE! I-I-I DON’T NEED TO BE PREPARED, PLEASE! P-PLEASE JUST PUT YOUR COCK INSIDE ME!”, but the little brother was impatient nonetheless.

Sans chuckled and looked up at Papyrus, making sure he had his attention before reaching for his shorts to push them down. The younger skeleton whined as the fully erect cock glowing blue, pushed against his inner thigh, but went no higher than there. “S-SANS...!”, Papyrus complained a bit.

Sans shushed him and gave a lopsided grin, “i really shouldn’t spoil ya’ so much. so for right now? why don’t ‘ya share what exactly ya’ like about what’s happening bro?” He added another finger inside Papyrus, knowing it wasn’t what he wanted, but knowing it felt good nonetheless.

Papyrus felt his need for the thick dick rubbing against him grow feverish and he whined in complaint, but then reasoned, his big brother had always taken good care of him, if he followed instructions now, he knew his needs would be attended to. And he had been such a bad boy too...of course he’d need to follow instructions.

“I-I! I LOVE HOW YOU’RE ON TOP OF ME, W-WITH ME TIED UP LIKE THIS, TRAPPING ME L-LIKE AN ANIMAL... AND AH! Y-YOUR FINGERS FEEL SO, SO GOOD INSIDE ME! YOUR COMMANDING VOICE IS...IS SO FUCKING SEXY AND I LOVE IT! I LOVE BEING UNDER YOUR CONTROL MMH-! HAAH! AN-AND BEING CALLED BROTHER, CALLING YOU BROTHER IS...IT’S IT’S SO...!”, Papyrus cut off with another loud moan. He was breathing hard, hips now bucking down onto his brother’s fingers moving so quickly inside him, pushing deeper and deeper. His brother was practically fucking him with his hand.

“p e r f e c t l y  s i n f u l”, Sans groaned out as he watched Papyrus’ face his voice echoing in that haunting way that neither of them could ever explain.

Papyrus felt himself nodding fervently in agreement, “YES! Y-YES! BROTHER I NEED YOU, NEED YOU INSIDE! M-MY PUSSY IS SO-! HAA-AH! IT’S THROBBING SO HARD! I NEED YOU! BROTHER, BROTHER PLEASE! I-!” Papyrus then shrieked as his body suddenly clamped up as he came hard on Sans’ fingers, “MNNNAAAAH! HAH!” His hips erratically bucked down onto the fingers being coated in Papyrus’ cum, trying to extend and savor the sensation of cumming so unexpectedly.

Sans smirked as he watched Papyrus’ eye lights - usually so tiny you couldn’t see them until up close - go large and hazy, orange wisps of magic floated out from them as he panted and whined. His little brother was so adorable.

Just as Papyrus started to realize what had happened and tried to focus to apologize for cumming too early, he felt his world shift. His face rolled to lie into the bed beneath him and his hips, still shaking, were pulled upwards. “S-SANS I...”, he turned his head to the side.

He let out a soft hum as Sans kissed the side of his mouth, “don’t say anything baby bro, that was hot as fuck.” Papyrus shifted a bit, blushing to himself reveling in the compliment. He then stiffened as he felt the length of Sans’ cock pushed right against his still sensitive and throbbing pussy, Papyrus groaned out, feeling the lips of his pussy practically suck at the hard length. His body was screaming for Sans to get on with it. Said skeleton chuckled deeply, “you’re really desperate for this aren’t ya’? tell me babe.”

“I WANT IT! I-I  _NEED_  IT! PLEASE BROTHER, FUCK ME!”, Papyrus cried as his bones shook in anticipation. He couldn’t hold out any more, he needed Sans inside him, or else he might just go mad with lust.

Sans’ hips shifted, and in one quick thrust, was abruptly sheathed inside Papyrus. “HAA! MMH YEEEESS! SHIT!”, Papyrus cried out and continued to do so as Sans didn’t wait to keep moving.

Sans rocked harshly into Papyrus’ pussy, the cum from his previous orgasm spurting out with every thrust. “hhaaa, you’re so dirty bro! look at‘cha, moaning like a little slut for me...”, the deep growl by Papyrus’ head reverberated through his bones made him whimper. His hips couldn’t seem to stop bucking back to feel more of his brothers hard unyielding thrusts.

His whole body was pushed down into the bed with each thrust, his hands clenched at air behind him unsure of what to grab at, his spine was arced at a blessedly painful angle that made his vision swim. He was in complete ecstasy and was sure he looked as lewd as he felt, tongue hanging out his mouth as he panted and screamed.

Sans’ thrusts all at once became scarily fast and Papyrus could feel himself getting close, he wouldn’t, couldn’t-! “NNAAAAH! SAAA-! HAAAA!”, he came vision going dark for a few moments. Everything faded out for a moment.

Papyrus could still hear his moaning, faint but still present, he could feel his hips being held in place as Sans pounded him from behind. “i-im’ma cum inside you bro, fill your pussy up t-to the brim...p-pap! Papyrus!”

And everything slowly came back.

Papyrus blinked slowly as he realized, he was now looking at the ceiling of his room, and he could feel Sans’ hands on him. One hand stroked his head slowly while the other just rested on his chest. “heya pap, you alright?”, Sans’ voice came from above his head.

With a quick glance Papyrus found that Sans was sitting next to him, and he’d been maneuvered so his head laid in his older brother’s lap. Taking a moment to assess himself so he could answer Sans’ question, Papyrus found that he was untied, and felt fine. He gave his arms and hands a few stretches. His arms, his pelvis and his spine were slightly sore, but Papyrus considered those small aches completely worth the treatment he’d just received. His magic was still activated in his pelvis, and he noted with no lack of lewd pleasure that when he shifted his hips, he could feel Sans’ cum shift around inside him. He breathed out sharply.

“I AM FINE SANS.”, Papyrus smiled up at him, “SANS THAT WAS...GLORIOUS.”

Sans chuckled and leaned down to kiss him, “was all your idea bro. more-or-less, heh. but uh...”

Papyrus blinked in confusion as Sans suddenly seemed serious in the gentle moment. His brother’s hand that had been stroking his head moved to cup the side of his face as his thumb absently stroked Papyrus’ cheek, “ ‘m sorry ‘bout reading your book but... you’re an adult papyrus, and as an adult you’re allowed to have needs and stuff. so if ya’ got a kink or something ya’ wanna try with me, please don’t hesitate to come and ask me. don’t hide ‘cause you think i’ll be disgusted or something... i could never be disgusted by someone as gorgeous and cool as you. ok?”

Papyrus felt his soul burn with emotions and he tried to keep himself from crying out of happiness, he had been so foolish. Of course his brother wouldn’t reject him over the kind of desires he had, it often escaped Papyrus’ mind, how kind and loving his brother was. Only nodding in response, not trusting his voice to stay level lest he cry, the younger skeleton reached up to pull Sans back down to kiss him.

Sans chuckled against his mouth, “love you, so much pap.”

Now that, Papyrus couldn’t stay silent to. “Yeah I...”, his voice cracked with emotion and he paused to try and recompose himself poorly, “I-I love you too Sans.” Their souls’ glowed together as they smiled.


End file.
